The present invention relates to a throttle trigger device for an internal combustion engine of a working tool, especially of a motor chainsaw, wherein a throttle trigger lock is provided that is connected to the throttle trigger with a spring. The throttle trigger and the throttle trigger lock are pivotably supported and form a unitary part together with the spring. The unitary part is arranged within the handle of the working tool.
Such a throttle trigger device is known from German Patent 39 16 414. The throttle trigger is arranged within the handle of the working tool and forms together with the throttle trigger lock a unitary component. The throttle trigger and the throttle trigger lock are arranged within the handle such that they are postioned atop one another so that an operator with the palm of his hand operates the throttle trigger lock and with one or more fingers of his hand the throttle trigger. The throttle trigger can only be pivoted when the throttle trigger lock is pressed down. The two levers (throttle trigger and throttle trigger lock) are connected with a spring to form a unitary part. The spring maintains the levers in their respective rest position. The operator must exert a pressure counter to the force of the spring in order to activate the throttle trigger. Each movement of one of the levers causes tension on the spring which acts as a reactive force on the other lever. The spring characteristics, i.e., the course of the spring force as a function of the pivot path, is substantially equal for both levers. Thus, the force acting on the throttle trigger in the full load position also acts on the palm of the operator. During longer operating periods this is not only uncomfortable, but can also be painful.
It is furthermore disadvantageous that the throttle trigger lock, the spring and the throttle trigger are arranged in one plane which results in a relatively great constructive height. The handle which receives the levers and the spring therefore must be constructed to be very large which is ergonomically unfavorable.
It is therefore an object of the present invention to provide a throttle trigger device in which the throttle trigger, the spring, and the throttle trigger lock form a unitary component such that constructively simple means, despite the use of a common spring, the throttle trigger is substantially unaffected by actuating forces of the throttle trigger lock.